In general when a human being loses his kidney function, unless a suitable kidney transplant is available, he must depend upon the dialysis process to remove the fluids and waste products from his system. This is generally done with a dialyzer machine, one which simulates the kidney function. The machine includes a hemodialyzer unit or dialyzer, which comprises two chambers or lumen, separated by an interface, this interface having the characteristics of a semi-permeable membrane and referred to hereinafter as `a membrane.` The first chamber receives blood from an artery in the patient under dialysis, and returns blood from that chamber to a vein of the patient. This is done with the arterial blood input connection and the venous blood output connection of the dialyzer. There are two additional connections, input and output dialysate connections, for receiving a dialysate fluid to pass it through the other chamber and out to a drain. This dialysate fluid is an artificial composition, including salts and water, passing adjacent to permeable membrane to remove those components from the blood of a molecular size that can pass through the interstices of the membrane. In general, conventional dialyzer systems provide a lesser pressure on the dialysate side of the membrane than on the blood side, to facilitate the passage of the waste materials and fluids through the membrane for discharge to the drain.
Over the past few years, dialyzers have been significantly improved and brought within a price range as low as $25 to $30. However, even though relatively inexpensive, these dialyzers cannot be used long because of the accumulation of matter in the pores or interstices of the membrane. The efficiency of the dialyzer is rapidly reduced with each dialysis treatment. At the present time, it is a common practice to clean the membrane with a cleaning solution, such as peroxide, which is flushed through the blood chamber. The cleaned dialyzer is then filled with a sterilizing solution, such as formalin. These operations are carried out manually. However the manual cleaning technique is tedious and expensive, more in the occupation of valuable technician time than in the use of fluids in the cleaning. In addition the technician doing the cleaning is exposed to the hepatitis B surface antigen, which is clearly undesirable.
It is therefore the principal object of the present invention to provide an automatic and fast acting cleaner for dialyzers, to substantially reduce the technician time formerly required in dialyzer cleaning.
A preferred object of the invention is to provide effective safeguards for the personnel doing the cleaning against cross-contamination from any bacteria or virus which may be in the dialyzer and the membrane.
Another preferred object of the invention is to provide a cleaner which is simple in design and maintenance and can be operated by relatively unskilled technicians.
It is common in the prior art to use proportioning systems, involving pumps, to supply cleaning and sterilizing fluids to the dialyzer. These proportioning systems are subject to failure and unnoticed loss of efficiency. It is therefore another preferred object of this invention to provide a cleaner having a system for supplying these fluids which is characterized by a high degree of reliability and consistent performance and provides solutions of constant composition.
Another preferred object of the present invention is to produce a cleaner which minimizes the possiblity of high-pressure cycles, or a significant pressure unbalance across the membrane which might reduce the efficiency of the dialyzer.
Another preferred object of the invention is to provide such a dialyzer cleaner which is readily modified to change the cleaning cycle or sequence as new techniques and substances are developed.